Weekly Update (June 1, 2016; Wk 05) - Greetings! Otani, Giffen, Weiss, Svendsen, Olfert

A downloadable PDF version of the complete Weekly Update for Week 5 (June 1, 2016) can be accessed here.  

This edition includes the return of the "Insect of the Week" featuring beneficial arthropods in 2016!

Subscribe to the Blog by following the instructions posted here!  You can receive automatic updates in your inbox through the growing season.

Questions or problems accessing the contents of this Weekly Update?  Please e-mail either Dr. Owen Olfert or Jennifer Otani.  Past “Weekly Updates” are very kindly archived to the Western Forum website by webmaster, Dr. Kelly Turkington.  

Weekly Update (June 1, 2016; Wk 05) - Weather Synopsis

Across the prairies, meteorological conditions were similar to long term average values for the period of May 22-29, 2016. The average temperature was 11.2 °C and was similar to the previous seven days. For the second week in a row temperatures were warmer in Manitoba and eastern Saskatchewan than western Saskatchewan and Alberta. 

This week’s rainfall was generally greater than long term average amounts. The region northeast of Edmonton and locations within southeastern Manitoba reported significant rainfall amounts while lower amounts were reported for southern Alberta and most of Saskatchewan.  The map below shows the Accumulated Precipitation the past 7 days (i.e., May 22-29, 2016): 

The map below reflects the Accumulated Precipitation for the Growing Season so far for the prairie provinces (i.e., April 1-May 30, 2016):

Compared to last week, soil moisture levels were predicted improve across most of the prairies:

The west was cooler compared to the east in terms of overnight temperatures over the last week.  The map below shows the Lowest Temperatures the Past 7 Days (May 24-30, 2016) across the prairies:

The map below shows the Highest Temperatures the Past 7 Days (May 24-30, 2016):

The updated growing degree day map (GDD) (Base 5ºC, March 1 – May 29, 2016) is below:

While the growing degree day map (GDD) (Base 10ºC, March 1 – May 29, 2015) is below:

The maps above are all produced by Agriculture and Agri-Food Canada.  Growers may wish to bookmark the AAFC Drought Watch Maps for the growing season.

Weekly Update (June 1, 2016; Wk 05) - 2016 Wind Trajectories (April 1 - May 30, 2016)

THE WEEK OF MAY 30, 2016:  Wind trajectory data processing by AAFC-Saskatoon Staff began in April.  Reverse Trajectories track arriving air masses back to their point of origin while Forward Trajectories predict favourable winds expected to arrive across the Canadian Prairies for the week of May 30, 2016:

Reverse trajectories (RT)
Mexico and southwest USA - Gainsborough SK and Carman MB continue to have RT’s that originate across southwestern USA  and Mexico this week.  

The following are RTs originating from the Pacific Northwest of the USA:

Forward trajectories (FT) 
None to report this week. 



Weather forecasts (7 day):
Winnipeg: https://weather.gc.ca/city/pages/mb-38_metric_e.html
Brandon: https://weather.gc.ca/city/pages/mb-52_metric_e.html
Saskatoon: https://weather.gc.ca/city/pages/sk-40_metric_e.html
Regina: https://weather.gc.ca/city/pages/sk-32_metric_e.html
Edmonton: https://weather.gc.ca/city/pages/ab-50_metric_e.html
Lethbridge: https://weather.gc.ca/city/pages/ab-30_metric_e.html
Grande Prairie: https://weather.gc.ca/city/pages/ab-31_metric_e.html


Downloadable versions of the Wind Trajectory Updates are available here.

Weekly Update (June 1, 2016; Wk 05) - Canola scouting chart

We again post our generalized canola scouting chart to aid in-field scouting on the Canadian prairies. The version below contains hyperlinks to help growers learn more about some of our insect pests and how to monitor for them. 

Weekly Update (June 1, 2016; Wk 05) - Diamondback moth

Diamondback moth (Plutellidae: Plutella xylostella) - Pheromone traps attracting male Diamondback moths (Fig. 1) have been deployed across the prairies.  

Figure 1. Diamondback moth.

Counts will be reported by the provincial staff in Saskatchewan.  Manitoba Agriculture and Rural Initiatives posted low DBM counts which can be reviewed within their second Insect Report.  Alberta Agriculture and Forestry has a live 2016 map reporting Diamondback moth pheromone trap interceptions.  A copy of the map (retrieved June 1, 2016) is below for reference.

Larval Monitoring:

Once the diamondback moth is present in the area, it is important to monitor individual canola fields for larvae.  Remove the plants in an area measuring 0.1 m2 (about 12" square), beat them on to a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 2. Diamondback larva measuring ~8mm long.

Note brown head capsule and forked appearance of prolegs on posterior.

Figure 3. Diamondback moth pupa within silken cocoon.

Economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1 m2 (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m2 (approximately 1-2 larvae per plant).

Biological and monitoring information for DBM is posted by Manitoba Agriculture, Food and Rural Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, and the Prairie Pest Monitoring Network.  

More information about Diamondback moths can be found by accessing the pages from the new "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide".  View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Weekly Update (June 1, 2016; Wk 05) - Flea beetles

Reminder - Flea Beetles (Chrysomelidae: Phyllotreta species) – Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Shot-hole feeding is the traditional damage in seedling canola but watch the growing point and stems of seedlings.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  - take  them scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings (Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page from the new "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.

Also refer to the previous Flea beetle post on the Blog.

Weekly Update (June 1, 2016; Wk 05) - Cutworms

Cutworms (Noctuidae) – Reminder - Keep an eye on fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  

Several species of cutworms  can be present in fields.  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to Manitoba Agriculture and Rural Initiatives cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 

More information about cutworms can be found by accessing the pages from the new "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide".  View an excerpt of ONLY the Cutworm pages from the new "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide".  The guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

For Manitobans....Last week's Insect Update includes great photos of dingy and redbacked cutworms plus monitoring tips which include how to discern these two species from one another.

For Saskatchewanians....Cutworms have been reported in several areas of the Province this spring. Affected crops include pea, lentil, barley and canola. If damage is significant and re-seeding is an option, seed first then spray an insecticide registered for cutworms in the applicable crop. Recommended economic thresholds for cutworms are:
   - 25 to 30 per cent stand reduction (canola)
   - 3 to 6 cutworms / square metre (wheat, barley, oats)
   - 2 to 3 cutworms / sq. metre (pea, lentil)
   - 4 to 5 / sq. metre (flax)

For Albertans..... Cutworms have been reported throughout the province the past week!  If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2016 Cutworm Reporting Tool”.  Once data entry occurs, your growers can view the live 2016 cutworm map.  A screen shot of the live map has been retrieved (01Jun2016) below for your reference and this week it includes additional reporting sites!

Weekly Update (June 1, 2016; Wk 05) - Pea leaf weevil

Pea leaf weevil (Sitona lineatus) - Be aware that higher densities of pea leaf weevil and higher levels of feeding damage have been observed in 2016 compared to 2015.  The 2015 pea leaf weevil risk map, based on damage observed on peas, is below as reference.

  

Review the updates provided by Carcamo for southern Alberta and Hartley related to southwest Saskatchewan posted last week.  

Reminder - Pea leaf weevils emerge in the spring primarily by flying (at temperatures above 17ºC) or they may walk short distances. Pea leaf weevil movement into peas and faba beans is achieved primarily through flight.  Adults are slender, greyish-brown measuring approximately 5 mm in length (Figure 1).

Figure 1. The pea leaf weevil, Sitona lineatus, measures ~5mm long (Photo: H. Goulet).

The pea leaf weevil resembles the sweet clover weevil (Sitona cylindricollis) yet the former is distinguished by three light-coloured stripes extending length-wise down thorax and sometimes the abdomen (Link here for the Pea leaf weevil monitoring protocol with photos of related weevils).  All species of Sitona, including the pea leaf weevil, have a short snout. 

Adults will feed upon the leaf margins and growing points of legume seedlings (alfalfa, clover, dry beans, faba beans, peas) and produce a characteristic, scalloped (notched) edge (Figure 2).  Females lay 1000 to 1500 eggs in the soil either near or on developing pea or faba bean plants from May to June.

Figure 2. Feeding notches on clam leaf of pea plant resulting from pea leaf weevil (Photo: L. Dosdall).

Weekly Update (June 1, 2016; Wk 05) - Alfalfa weevil

Alfalfa Weevil (Hypera postica) – The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer”.  The green larva featuring a dorsal, white line down the length of its body has a dark brown head capsule and will grow to 9mm long.  Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon).

Degree-day maps of base 9°C are now being produced by Soroka, Olfert, and Giffen (2016) using the Harcourt/North Dakota models.  The aim or the modelling is to predict the development of Alfalfa weevil (Hypera postica) across the prairies and to help growers time their in-field scouting as second-instar larvae are predicted to occur.  Compare the following predicted development stages and degree-day values copied below (Soroka 2015) to the map below.

This week, alfalfa growers situated within ANY shade of purple should prioritize scouting for second instar larvae and compare it to the action threshold for alfalfa weevil which varies according to end use and crop stage.  

Use the figure below as a visual reference to identify alfalfa weevil larvae.  Note the white dorsal line, the tapered shape and the dark head capsule.

Weekly Update (June 1, 2016; Wk 05) - Predicted Bertha Armyworm Development

Bertha armyworm (Lepidoptera: Mamestra configurata) - Bertha armyworm (BAW) pupal development is progressing well.  Pheromone traps should be deployed in areas highlighted yellow in the map below.

Those monitoring BAW pheromone traps may want to compare trap “catches” to the following reference photo kindly shared by Saskatchewan Agriculture below:

Weekly Update (June 1, 2016; Wk 05) - Predicted Grasshopper Development

Grasshoppers (Acrididae) – This past week, warm conditions conditions in Saskatchewan were predicted to result in enhanced development. 

For the week of May 29, 2016, the predicted mean embryological development was 87% and indicates that grasshopper hatch will continue to progress over the next week to ten days. The model predicted that 23% of the hatch is complete (compared to 13% predicted last week). Approximately 15% of the population was predicted to be in the first instar and 7% in the second instar.

The following image showing various stages of the clearwinged grasshopper is provided below - note that adults have wings extending the length of the abdomen whereas nymphs lack wings but develop wing buds that will eventually mature to wings.  

Biological and monitoring information related to grasshoppers in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta, British Columbia and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the new "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" - both English-enhanced or French-enhanced versions are available.

Weekly Update (June 1, 2016; Wk 05) - Provincial Insect Pest Reports

Provincial entomologists provide insect pest updates throughout the growing season so we have attempted to link to their most recent information: 

- Manitoba's Insect and Disease Update (May 25, 2016, prepared by John Gavloski and Pratisara Bajracharya).
- Saskatchewan's Unofficial Insect Update - which included Pea leaf weevil, cutworms, and forest tent caterpillars.
- Watch for Alberta Agriculture and Forestry's Call of the Land for updates from Scott Meers  who recently gave a summary (posted on May 26, 2016).

Weekly Update (June 1, 2016; Wk 05) - Crop Protection Guides

Reminder - Crop Protection Guides – If you don’t have a copy of your province’s Crop Protection Guide, please make use of these links to access:

• Saskatchewan's Crop Protection Guide
• Manitoba's Guide to Crop Protection Guide 
• Alberta's Crop Protection or Blue Book 
• Western Committee on Crop Pests Guidelines for the Control of Crop Pests 

Weekly Update (June 1, 2016; Wk 05) - Weather Radar

If fields are near one of Environment Canada’s radar stations, consider accessing weather radar maps in video format that show either the past 1 OR 3 hours of spatio-temporal maps of precipitation events.  These maps can help growers review where and how much precipitation fell nearby.

Screen shots of Environment Canada’s webpages are below for reference and red text and arrows have been added to help you navigate.

Weekly Update (June 1, 2016; Wk 05) - Monarch migration

Track the migration of the Monarch butterflies and they move north by checking the 2016 Monarch Migration Map!  Sightings have been reported in southern Ontario and southern British Columbia by now!  A screen shot of the map has been placed below as an example (retrieved 01Jun2016) but follow the hyperlink to check the interactive map!

Insect of the Week (May 30, 2016) - Ground beetles

Ground beetles (predator)

Last year, the focus of the Insect of the Week was crop pests. This year, we’re changing things up and highlighting the many natural enemies that help you out, silently and efficiently killing off crop pests. [note: featured Insects of the Week in 2015 are available on the Insect of the Week page] 

This week’s Insect of the Week is the ground beetle. There are nearly 400 known ground beetle species on the prairies. Some of these provide important pest control service: eating redbacked cutworm eggs, grasshopper eggs, pea leaf weevil eggs, cabbage maggots and diamondback moth larvae. See more information in the new Field Crop and Forage Pests and their Natural Enemies in Western Canada - Identification and Management Field Guide for identification, life cycle and conservation options (download links for field guide available on the Insect of the Week page).

The ground beetle Pterostichus melanarius can help prevent pest outbreaks of diamondback moth (Plutella xylostella). © Canadian Biodiversity Information Facility (www.cbif.gc.ca)

For those that just can’t get enough about the fascinating world of insects, Ground Beetles (Coleoptera: Carabidae) of the Prairie Grasslands of Canada is a recent literature review on the topic.